Just weeks before psychiatry’s new diagnostic “bible”—the DSM 5— is set to be released, the world’s major funder of mental health research has announced that it will not use the new diagnostic system to guide its scientific program, a change some observers have called “a cataclysm” and “potentially seismic.” Dr. Thomas Insel, the director of the National Institute on Mental Health, said in a blog post last week that “NIMH will be re-orienting its research away from DSM categories.”
The change will not immediately affect patients. But in the long run, it could completely redefine mental health conditions and developmental disorders. All of the current categories — from autism to schizophrenia — could be replaced by genetic, biochemical or brain-network labeled classifications. Psychiatrists, who are already reeling from the conflict–filled birth of the fifth edition of the Diagnostical and Statistical Manual of Mental Disorders, are feeling whipsawed.
Insel, for his part, is lobbying for a more comprehensive approach. For scientific purposes, he argues, the DSM may have outlived its usefulness. He writes:
Unlike our definitions of ischemic heart disease, lymphoma, or AIDS, the DSM diagnoses are based on a consensus about clusters of clinical symptoms, not any objective laboratory measure. In the rest of medicine, this would be equivalent to creating diagnostic systems based on the nature of chest pain… Imagine deciding that EKGs were not useful because many patients with chest pain did not have EKG changes. That is what we have been doing for decades when we reject a biomarker because it does not detect a DSM category. We need to begin collecting the genetic, imaging, physiologic, and cognitive data to see how all the data – not just the symptoms – cluster and how these clusters relate to treatment response…Patients with mental disorders deserve better.
The NIMH has outlined a new diagnostic system — called Research Domain Criteria (RDoC) — that could ultimately replace the DSM, but it’s not yet ready for prime time. For the time being, NIMH and the psychiatrists who use the manual will continue to abide by existing classifications for diagnosing patients and getting treatment reimbursed. “Some people have the idea that we’re trying to ditch or diss the DSM and that’s not a fair assessment,” says Insel.
Dr. David Kupfer, the chair of the APA’s DSM 5 task force said in a statement responding to Insel’s post, “The new manual, due for release later this month, represents the strongest system currently available for classifying disorders… Efforts like the National Institute of Mental Health’s Research Domain Criteria (RDoC) are vital to the continued progress of our collective understanding of mental disorders. But they cannot serve us in the here and now, and they cannot supplant DSM-5.”
But Dr. Eric Hollander, who chaired the DSM research planning agenda for obsessive-compulsive spectrum disorders, says it’s hard to deny that the NIMH appears to be rallying support for a different approach to mental-health classification. “I do think it does represent a lack of interest and faith on behalf of NIMH for the DSM process and an investment in alternative diagnostic systems,” says Hollander, who is director of the autism and obsessive-compulsive spectrum disorder program at Montefiore/Albert Einstein School of Medicine in New York.
Numerous forces currently undermine accurate diagnosis in psychiatry. To start, researchers have so far been unable to find specific biomarkers like brain scan results or genetic tests to definitively diagnose conditions like depression and to predict which treatments will best help which patients. Secondly, many psychiatric patients have symptoms of more than one disorder and many are clearly ill without meeting any diagnosis precisely. “That tells you we’re not cutting nature at its joints, that it’s not an accurate way to categorize,” says Insel.
Finally, pressures from pharmaceutical companies have led to a massive increase in prescribing of psychiatric medications and labeling of patients to justify that prescribing. Critics of the DSM 5 process have noted that 70% of people serving on its committees to define specific diagnoses have financial ties to pharmaceutical companies, up from 57% for DSM IV.
“People with mild problems are overmedicated and people with severe problems are terribly under-medicated because access to care is terribly underfunded,” says Dr. Allen Frances, a leading critic of DSM 5, who chaired the DSM IV revision process. He is concerned that the new edition, with its loosening of criteria in several major disorders, will result in even further overmedication.
“We’ve used a syndromal approach to research for the last 33 years,” he says, “It hasn’t paid off well.” Indeed, even the pharmaceutical industry seems to be backing away from psychiatry, with almost all of the major players trimming research and development of psychiatric drugs following recent failures.
“I look at the data and I’m concerned,” says Insel. “I don’t see a reduction in the rate of suicide or prevalence of mental illness or any measure of morbidity. I see it in other areas of medicine and I don’t see it for mental illness. That was the basis for my comment that people with mental illness deserve better.” Adds Hollander, “There’s been a huge gap between some of our basic science information and our ability to develop new treatments because those don’t necessarily map onto DSM diagnoses.”
That’s why NIMH so desperately wants a new system. Searching the genome for correlates of “schizophrenia” or “ADHD” hasn’t turned up any single gene or group of genes that accounts for most of the risk or has led to a new type of treatment. Nor have brain scan findings been able to reliably distinguish between psychiatric conditions as now defined or predict which medications or therapies will help.
Instead, RDoC suggests that by precisely targeting one symptom that may occur in multiple disorders— for example, repetitive behavior— it will be easier to find brain and genetic connections than it would be to continue to study a widely varied group of people with a disease like obsessive-compulsive disorder that’s defined by that symptom, plus many others.
Of course, such complex diagnostic issues aren’t unique to psychiatry: classification in areas of medicine as seemingly clearcut as oncology can be fuzzy as well. Recent studies find, for instance, that certain types of severe uterine cancer may share more in common genetically with certain breast cancers than they do with milder uterine disease. The same seems to be true in psychiatry, with new studies finding common genetic roots for ADHD, schizophrenia and autism.
With RDoC, Insel wants to bring this same type of what cancer specialists call “precision medicine” to brain disorders, classifying them not simply by symptoms but by genetic analysis and identifying what brain circuits are most affected. Building on a systems approach, RDoC might be able to find a comprehensive regimen that can be individualized for a person’s particular problems, not just an overall classification.
However, just because today’s diagnoses are far from perfect doesn’t mean that mental illness isn’t real or that DSM diagnoses are entirely useless— just as the fact that certain breast and uterine cancers are genetically similar and may require the same treatment doesn’t make breast or uterine cancer “fake” or irrelevant categories.
“We shouldn’t throw out the baby of clinical diagnosis with the bathwater of its limits. It’s still absolutely necessary and often very helpful,” says Frances. “We need to give reassurance for people operating under the current diagnostic system that it makes sense. It’s not the best way to go forward in research, but it’s the best available form of clinical treatment and planning available now.”
Insel doesn’t object. He says “there’s all kinds of value in using the current [system]” to treat patients whose disorders, whatever they may eventually be called, cause real suffering right now and are dependent upon insurance reimbursement that requires a diagnosis code.” He adds, “We’ve worked really closely [with the American Psychiatic Association on the] DSM. This is not meant in any way to be competitive. We don’t have anything [else] clinicians can use in 2013.” With any luck, RDoC or some more refined diagnostic system will soon change that and finally offer better treatments for some of medicine’s most painful and debilitating disorders.